Evaluation on Soil Heavy Metal Pollution around Tailing Areas: A Case Study of Ag-Sb Deposit in Northeastern Guangdong

In October 2012,an evaluation using potential ecological hazard risk index was carried out on soil heavy metal pollution around AgSb deposit tailing areas in northeastern Guangdong. Results indicate that( i) soil heavy metal pollution is mainly Cd-Ni compound pollution,including Cd content 0. 31- 2. 66 mg / kg( average content is 1. 11 mg / kg),the situation of exceeding standard is serious( the rate of exceeding standard is 100%); the total potential ecological hazard risk index( RI) is between 50 and 300,and it is moderate pollution;( ii) in soil heavy metal content,only Ni and Cu are positively correlated. Since there is certain degree of Ni pollution in this deposit,the synergetic effect of Cu and Ni may deteriorate Ni pollution.

Mineralization at low temperature and its relation with organic substances——Taking Songxi Ag-Sb ore deposit in northeast Guangdong as an example

1 Geological setting and samples Songxi Ag-Sb ore deposit is located in the southern margin of Yongding-Mexian Paleozoic depressionof South China Caledonian orogenic belt, and the northern margin of Zhaigang Mesozoic volcanic basin,where a series of faults and folds formed with northwest tectonic directions. The sedimentary rocks arecomposed of Songling Group of low Jurassic system, Zhangping Group of middle Jurassic system and Quaternary System in which Songling Group can be divided into 3 lithostratigraphic units regionally, where thetwo of the units can be found there, i.e. the middle unit with gray-yellow quartz sandstone, fine sandstone and siltstone, and the upper with black shale and tuff, in which layered Ag-Sb ore bodies are deposited, and especially in the low part of quartz sandstone, siltstone, bioclastic limestone and the alteredbasalt are the main ore-bearing rocks. The ore bodies can be divided into two types of mineralization, i.e. bedded or bedded-like types and vein type.

粤东北银锑矿尾矿区周边土壤重金属污染评价

对粤东北银锑矿尾矿区周边土壤的理化性质、重金属含量及其与理化性质相关性分析的基础上,应用Hakanson潜在生态危害指数对其危害程度进行评价。结果表明：矿区土壤呈酸性,pH3.40-6.94,土壤相对较贫瘠;土壤重金属污染以Cd污染为主,Cd含量为0.31-2.66mg·kg^-1（平均含量为1.11mg·kg^-1）,严重超标;从总潜在生态危害指数看,各样点均界于50≤RI〈300之间,属中污染;土壤理化性质及其与土壤重金属污染间存在不同程度的相关性,其中,距离与pH呈显著正相关,pH与交换性酸、与Cd分别呈显著、极显著的负相关;Cu与Ni含量呈显著正相关。

粤东北银锑矿区周边土壤Cd污染及沙田柚、香蕉的富集特征

以粤东北银锑矿区周边土壤为研究对象,在分析矿区土壤理化性质、Cd含量及其与土壤理化性状相关性的基础上,探讨了沙田柚、香蕉对Cd的富集特征。结果表明:(1)矿区土壤呈酸性(pH4.24~6.56),土壤相对较贫瘠;(2)土壤Cd污染十分严重,土样Cd含量平均值为10.20 mg/kg,且Cd含量与土壤pH呈极显著负相关;(3)沙田柚体内Cd含量为1.56-4.28 mg/kg、香蕉体内Cd含量为1.71-5.46 mg/kg,植物不同各部位Cd含量的差异表现为:根>茎叶>果,但沙田柚、香蕉果实中Cd含量仅在4号土壤中低于国家二级标准,从食用安全性考虑,建议沙田柚、香蕉栽种时应选择在距离尾矿区500 m以外的地区为好;两种果木的富集系数范畴为0.31~0.45、转运系数范围为0.57~0.75,均较低,表明沙田柚、香蕉均不是Cd的超富集植物。

粤东北银锑矿尾矿区土壤重金属含量及对绿豆种子萌发的生态毒性

研究粤东北银锑矿尾矿区周边土壤的理化性质、6种重金属元素（Pb、Zn、Cu、Cd、Ni、Cr）的含量以及土壤重金属污染对绿豆种子萌发的影响,结果表明：（1）p H界于4.24~6.56之间,土壤较贫瘠;（2）土壤重金属污染属Cd-Ni-Zn复合型污,其中,Cd含量为0.72~1.93mg/kg（平均含量为1.22 mg/kg）,超标严重;（3）发芽指数为5.4~7.0,各样点间虽有差异,但差异不显著,而活力指数（30.1~44.0）、苗长度（4.3~7.1cm）均达到了差异极显著水平（P〈0.01）.

粤东北仁差盆地南部某矿床地球化学特征及成因分析

本文在系统详细的野外地质工作基础上,以仁差盆地南部某矿床为研究重点,系统收集该区地质、地球物理、地球化学资料,对矿床地质特征、矿床成因进行研究分析。认为该矿床为次火山岩型铀矿床,含矿岩性主要为次流纹斑岩,矿体呈脉状、透镜状,矿床达中型规模。矿石物质成分较简单,主要金属矿物有沥青铀矿、铀石、铀钍石。该区铀源、热源、水源丰富,成矿物质和水体来源具有明显的双重性,其矿床成因应属于与火山作用有关的,有火山热液、火山热水和地下水联合作用叠加再造富集而成的复成因(构造+岩性+热液蚀变)矿床,它具有内生与外生的双重性,经历了内生——外生——表生作用的复杂过程。